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Objective: To evaluate the efficacy and safety of omalizumab in patients with refractory allergic asthma using meta-analysis. Methods: We searched databases including PubMed, Web of Science, Embase and the website of ClinicalTrials. gov registry for randomized controlled trials (RCTs), using the search terms: ("anti-IgE" OR "anti-immunoglobulin E" OR "anti-IgE antibody" OR "omalizumab" OR "rhuMAb-E25" OR "Xolair") AND ("allergic asthma"). The time was up to September 19th 2020. Review Manager 5.4 software and Stata16 software were used to calculate pooled RR or WMD, perform heterogeneity test, and assess publication bias. Results: Fifteen RCTs with 6 316 patients in total (omalizumab, n=3 469; placebo, n=2 847) met our selection criteria. Comparing with placebo, omalizumab reduced the risk of asthma exacerbations during both stable-inhaled corticosteroid (ICS) phase (RR=0.69, 95%CI: 0.63-0.75, P<0.001; I2=39.0%, P=0.090) and ICS-reduction phase (RR=0.55, 95%CI: 0.46-0.66, P<0.001; I2=41.0%, P=0.180), reduced emergency visits (RR=0.53, 95%CI: 0.38-0.73, P<0.001; I2=0, P=0.420), made a significant reduction in dosage of ICS (RR=1.35, 95%CI: 1.25-1.45, P<0.001; I2=22.0%, P=0.280) and even withdrew from ICS completely (RR=1.80, 95%CI: 1.41-2.31, P<0.001; I2=57.0%, P=0.070). Omalizumab significantly improved asthma-related quality of life (RR=1.81, 95%CI: 1.51-2.17). The use of rescue bronchodilators was significantly reduced in the omalizumab group (RR=0.78, 95%CI: 0.67-0.92) but there was no significant difference in the dosage of rescue bronchodilators (puff per day) (WMD=-0.32, 95%CI: -0.77-0.13). Patients taking omalizumab did not increase the frequency of any adverse events (RR=1.01, 95%CI: 0.98-1.03) and serious adverse events (RR=0.89, 95%CI: 0.74-1.06). Conclusions: Omalizumab is an ideal adjunctive treatment for refractory allergic asthma with good efficacy and safety. Further randomized controlled trials are needed to determine the appropriate duration of treatment.
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Antiasmáticos , Asma , Omalizumab , Antiasmáticos/efectos adversos , Asma/tratamiento farmacológico , Humanos , Omalizumab/efectos adversosRESUMEN
Objective: To investigate the changes of natural killer(NK) cell function, and clarify the effect of granulocytic myeloid derived suppressor cells (G-MDSCs) on NK cell functionality in patients with treatment-naive chronic hepatitis C (CHC) who were cured by direct-acting antiviral agents (DAAs). Methods: Thirteen treatment-naive CHC patients and 13 healthy controls were prospectively included in this study from March 2016 to January 2017. They were divided into case group and control group, respectively. The patients of case group,6 males and 7 females aged 21-65 years old with an average of (37±14),were treated with daclatasvir and asunaprevir combination (DCV/ASV) at the Department of Infectious Diseases, Fifth Medical Center of Chinese PLA General Hospital. While 13 healthy individuals, 6 males and 7 females aged 21-57 (36±11) years old, were enrolled as healthy controls(control group). Flow cytometry was used to determine the immunological characteristics of peripheral blood NK cells subset, and detect the frequencies of gMDSCs in peripheral blood of people in two groups. It was specifically notes that CHC patients of case group would be detected before, during and after treatment. The correlations between gMDSCs and each NK cell subset function were also examined. The impact of gMDSCs on NK cell functionalities and the relevant regulatory mechanisms were explored using co-culture experiments of sorted NK cells and gMDSCs in vitro. Results: Compared with healthy controls, the decreased IFN-γ production[M(Q1,Q3)] [3.182 (2.757, 4.237) vs 6.675 (4.476, 8.280),1.434 (1.127, 2.434) vs 3.045 (1.680, 4.856), 2.611 (1.749, 3.498) vs 5.160 (4.232, 7.683)] and increased CD107a degranulation [9.314 (7.838, 13.543) vs 3.480 (2.938, 6.824), 2.544 (1.366, 4.768) vs 0.552 (0.408, 1.560), 10.339 (9.145, 12.534) vs 3.488 (3.117, 5.651)] (all P<0.05) were found on NK cell and its subsets. The frequencies of gMDSCs and plasma concentration of arginase-1 in CHC patients was significantly higher than that in healthy controls [7.050 (4.180, 12.538) vs 1.440 (0.444, 2.261), 114.278 (68.492, 163.724) vs 64.753 (50.809, 93.278)](all P<0.05). The production of IFN-γ was increased and the secretion of CD107a was decreased in NK cell and its subsets after DAAs treatment (P<0.05). The frequencies of gMDSCs and plasma arignase I levels were also decreased in CHC patients treated with DAAs (P<0.05).The results of the study indicated that the frequencies of G-MDSCs were inversely associated with the levels of IFN-γproduction of NK cells and CD56dim NK cells in CHC patients (r=0.668, -0.750, respectively, both P<0.05). In addition, the frequencies of gMDSCs were positively associated with the expression of CD107a in the CD56bright NK cell subset (r=0.711, P=0.021). In vitro, the inhibition of gMDSCs on the IFN-γ production of NK cells was demonstrated in the co-culture experiments of sorted NK cells and gMDSCs, and blocking arginase I can significantly increase the ability of NK cells to produce IFN-γ, restore NK cell IFN-γ production. Conclusions: gMDSCs in peripheral blood of CHC patients has been shown to suppress NK cell IFN-γ production in an arginase I-dependent manner. Direct-acting antiviral-mediated clearance of HCV is associated with the normalization of NK cell function and gMDSCs frequency.
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Hepatitis C Crónica , Células Supresoras de Origen Mieloide , Adulto , Anciano , Antivirales/uso terapéutico , Femenino , Citometría de Flujo , Hepatitis C Crónica/tratamiento farmacológico , Humanos , Células Asesinas Naturales , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
A general feature of unconventional superconductors is the existence of a superconducting dome in the phase diagram. Here we report a series of discrete superconducting phases in the simplest iron-based superconductor, FeSe thin flakes, by continuously tuning the carrier concentration through the intercalation of Li and Na ions with a solid ionic gating technique. Such discrete superconducting phases are robust against the substitution of 20% S for Se, but they are vulnerable to the substitution of 2% Cu for Fe, highlighting the importance of the iron site being intact. The superconducting phase diagram for FeSe derivatives is given, which is distinct from that of other unconventional superconductors.
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To calculate resting energy expenditure (REE) in patients receiving invasive mechanical ventilation and compare different predictive equations with indirect calorimetry(IC).A total of 60 patients in intensive care unit(ICU) were enrolled. Measure calculating daily REE in the first week included IC, Harris-Benedict formula, Penn State formula and Swinamer formula. Daily REE did not exhibit significant difference in the first week of mechanical ventilation by IC (all P>0.05).All patients' REE values by IC were higher than those by Harris-Benedict formula (all P<0.01). By Penn State formula, REE in day l, 2, and 5 were comparable (all P>0.05) with those by IC, whereas the consistency between the two methods was poor. Similarly, daily REE by Swinamer formula calculation in the first week did not show significant difference (all P>0.05), with acceptable consistency as IC. Resting energy expenditure in patients receiving invasive mechanical ventilation dose not significantly change during the first week. Swinamer formula is more accurate than other equations when IC is considered as the standard method.
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Calorimetría Indirecta , Metabolismo Energético , Respiración Artificial , Femenino , Humanos , Unidades de Cuidados IntensivosRESUMEN
FKBP38 (also known as FKBP8) is a unique member of the FK506-binding protein (FKBP) family, and its role is controversial because it acts as an upstream regulator of the mTOR signaling pathway, which controls cell growth, proliferation, and differentiation. This study aimed to explore the role of FKBP38 in the activation of mTOR signaling in Cashmere goat (Capra hircus) fetal fibroblasts. To construct a Cashmere goat FKBP38 siRNA eukaryotic expression vector that targets FKBP38 mRNA, we designed shRNA based on the gene sequence deposited in GenBank (accession No. JF714970) and synthesized a DNA fragment encoding the shRNA. The DNA fragment was inserted into the pRNAT-U6.1/Neo vector to construct an expression vector of shRNA, which was labeled pRNAT-FKBP38-shRNA. The recombinant plasmid was used to transfect Cashmere goat fetal fibroblasts (GFb) using lipofectamine™2000. We found that cells were successfully transfected with pRNAT-U6.1/Neo-FKBP38-shRNA. Green fluorescence could be observed in cells following 48-h transfection. Proteins were then isolated from GFbs transfected with pRNAT-FKBP38-shRNA and from control cells, and protein expression was analyzed by western blot. Expression of FKBP38 decreased and mTOR signaling was activated, which induced the phosphorylation of mTOR, S6, and 4EBP1. Thus, FKBP38 gene-silencing activates mTOR signaling in goat cells.
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Fibroblastos/metabolismo , Silenciador del Gen , Cabras/genética , Cabras/metabolismo , ARN Interferente Pequeño/genética , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Proteínas de Unión a Tacrolimus/genética , Animales , Secuencia de Bases , Células Cultivadas , Expresión Génica , Orden Génico , Vectores Genéticos/genética , Fosforilación , ARN Mensajero/química , ARN Mensajero/genética , ARN Interferente Pequeño/química , Proteínas Quinasas S6 Ribosómicas/metabolismo , Proteínas de Unión a Tacrolimus/química , TransfecciónRESUMEN
Objective: To explore the cutoff value for assessing small airway dysfunction in children with asthma. Methods: A total of 364 asthmatic children aged 5 to 14 years, with normal ventilatory function, followed up at the Asthma Clinic of the Children's Hospital of Capital Institute of Pediatrics from January 2017 to January 2018, were selected as the case group. Concurrently, 403 healthy children of the same age range and without any symptoms in the community were chosen as the control group, and pulmonary function tests were conducted. The values of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), forced expiratory flow at 50% of FVC (FEF50), forced expiratory flow at 75% of FVC (FEF75) and maximum mid-expiratory flow (MMEF) were compared between case group and control group. Statistical tests such as t-test, χ2 test, or Mann-Whitney U test were used to analyze the differences between the groups. Receiver operating characteristic (ROC) curves were constructed, and the maximum Youden Index was utilized to determine the optimal cutoff values and thresholds for identifying small airway dysfunction in asthmatic children. Results: This study comprised 364 children in the case group (220 boys and 144 girls) and 403 children in the control group (198 boys and 205 girls). The small airway parameters (FEF50%pred, FEF75%pred, MMEF%pred) in the asthmatic group were significantly lower than in the control group (77% (69%, 91%) vs. 95% (83%, 109%), 67% (54%, 82%) vs. 84% (70%, 102%), 76% (66%, 90%) vs. 97% (86%, 113%), Z=12.03, 11.35, 13.66, all P<0.001). The ROC curve area under the curve for FEF50%pred, FEF75%pred, MMEF%pred was 0.75, 0.74, and 0.79, respectively. Using a cutoff value of 80% for FEF50%pred achieved a sensitivity of 56.9% and specificity of 81.4%. A cutoff value of 74% for FEF75%pred resulted in a sensitivity of 67.3% and specificity of 69.2%. Finally, using a cutoff value of 84% for MMEF%pred achieved a sensitivity of 67.9% and specificity of 77.2%. Conclusion: In the presence of normal ventilatory function, utilizing FEF50<80% predicted or MMEF<84% predicted can accurately serve as criteria for identifying small airway dysfunction in children with controlled asthma.
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Asma , Masculino , Femenino , Humanos , Niño , Asma/diagnóstico , Volumen Espiratorio Forzado , Capacidad Vital , Pruebas de Función Respiratoria/métodos , Curva ROCRESUMEN
OBJECTIVE: Acute myocardial infarction (AMI) is the main cause of sudden death in the world. The aim of this paper was to explore the role of microRNA-18-5p (miR-18-5p) in myocardial infarction (MI) and its potential mechanism. MATERIALS AND METHODS: The expression of miRNA and protein was detected using quantitative reverse-transcription polymerase chain reaction (RT-PCR) analysis and Western blot. The level of oxidative stress of cardiomyocytes was evaluated by detecting the contents of Superoxide dismutase (SOD), Reactive oxygen species (ROS) and Malondialdehyde (MDA). Caspase-3 activity assay, flow cytometry and TUNEL staining were employed to evaluate apoptosis of myocardium. Dual-Luciferase reporter gene assay was used to prove whether miR-18-5p targeted RUNX1. RESULTS: MiR-18-5p was down-regulated in hypoxia-treated H9c2 cells. Hypoxia treatment induced oxidative stress and apoptosis of H9c2 cells. The oxidative stress of H9c2 was manifested by the decrease of SOD activity, the increase of ROS and MDA levels, and the apoptosis of H9c2 was shown by the increase of caspase-3 activity and apoptosis rate. MiR-18-5p mimic was transfected into H9c2 cells and successfully up-regulated miR-18-5p. And overexpression of miR-18-5p markedly inhibited the oxidative stress and apoptosis caused by hypoxia in H9c2 cells. Through bioinformatics analysis and Dual-Luciferase reporter gene assay, RUNX1 was proved to have binding sites for miR-18-5p. Furthermore, knocking down RUNX1 using small interfering RNA-RUNX1 (siR-RUNX1) significantly protected H9c2 cells from oxidative stress and apoptosis. CONCLUSIONS: MiR-18-5p expression was decreased in hypoxia-treated H9c2 cells. Overexpression of miR-18-5p alleviated hypoxia-induced oxidative stress and apoptosis in H9c2 cells via targeting RUNX1.
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Subunidad alfa 2 del Factor de Unión al Sitio Principal , MicroARNs , Apoptosis , Subunidad alfa 2 del Factor de Unión al Sitio Principal/genética , Subunidad alfa 2 del Factor de Unión al Sitio Principal/metabolismo , Hipoxia/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Miocardio/metabolismo , Miocitos Cardíacos/metabolismo , Estrés Oxidativo/genéticaRESUMEN
We present energy-resolved angular distributions of photoelectrons generated in above-threshold ionization (ATI) of nonaligned diatomic molecules N2 and O2 in high-intensity short laser pulses, with emphasis on the most energetic part of the spectra. The angular distribution for photoelectrons with energy of 10U(p) (U(p): ponderomotive energy), i.e., the plateau cutoff in ATI spectra, is found to be broader in O2 than in N2. Resorting to the analyses from both an S-matrix theory and an intuitive semiclassical model, we attribute the observation to the effect of the ground state molecular orbital structure on high-energy electron emission in strong-field molecular ionization.
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The emergent phenomena such as superconductivity and topological phase transitions can be observed in strict two-dimensional (2D) crystalline matters. Artificial interfaces and one atomic thickness layers are typical 2D materials of this kind. Although having 2D characters, most bulky layered compounds, however, do not possess these striking properties. Here, we report quasi-2D superconductivity in bulky AuTe2Se4/3, where the reduction in dimensionality is achieved through inducing the elongated covalent Te-Te bonds. The atomic-resolution images reveal that the Au, Te, and Se are atomically ordered in a cube, among which are Te-Te bonds of 3.18 and 3.28 Å. The superconductivity at 2.85 K is discovered, which is unraveled to be the quasi-2D nature owing to the Berezinsky-Kosterlitz-Thouless topological transition. The nesting of nearly parallel Fermi sheets could give rise to strong electron-phonon coupling. It is proposed that further depleting the thickness could result in more topologically-related phenomena.Emergent phenomena often appear in crystals in the two-dimensional limit but are rare in bulky compounds. Here, Guo et al. report a quasi-two-dimensional superconductivity in a bulk material AuTe2Se4/3 at 2.85 K, potentially owing to a topological transition.
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This experiment was conducted to investigate the effect of dietary arsenic (As) levels on growth performance, serum biochemistry, and the retention of iron, copper, and zinc in tissues of growing and finishing pigs. Ninety-six crossbred pigs were randomly allotted to four dietary treatments. The corn-soybean basal diets were supplemented with 0, 10, 20, and 30 mg As/kg. Arsenic trioxide was used as the arsenic source. The feeding experiment lasted for 78 d. The results showed that the high arsenic diet decreased average daily gain (ADG) (p<0.05) and increased feed gain ratio (F/G) (p<0.05). Arsenic intake significantly increased (p<0.05) serum gamma-gultamyltransferase (GGT), glutamic-pyruvic transaminase (GPT), and alkaline phosphatase (ALP) activities, and decreased (p<0.05) total protein, urea nitrogen, creatinine, and triglycerides. Glutamic-oxalacetic transaminase (GOT) activity, albumin, and cholesterol were not affected (p>0.05). Arsenic feeding elevated (p<0.05) liver and kidney copper concentration, but reduced (p<0.05) copper concentration in heart, bile, and lymphaden of intestine mesentery. There were increases in iron levels in liver, bile, spleen, thymus, and pancreas in pigs fed the high As diets (p<0.05), but iron contents in kidney, heart, and serum were decreased by the arsenic treatment (p<0.05). Zinc concentrations were increased (p<0.05) in liver, kidney, and thymus of pigs with arsenic treatment, but decreased (p<0.05) in bile and lymphaden of intestine mesentery. This study suggested that high dietary As levels could alter serum biochemical parameters and the retention of copper, iron, and zinc in the viscera of growing and finishing pigs.
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Alimentación Animal , Arsénico/farmacología , Suplementos Dietéticos , Glycine max , Porcinos/crecimiento & desarrollo , Oligoelementos/sangre , Aumento de Peso/efectos de los fármacos , Animales , Arsénico/sangre , Enzimas/sangre , Porcinos/sangreRESUMEN
OBJECTIVE: To study the protective effect for Chinese medicine of promoting blood circulation and removing blood stasis (PBCRBS) on vascular endothelial cells (VEC) in rats, aiming at further research on the mechanism of blood stasis syndrome and PBCRBS. METHOD: Establishing a model of blood stasis with endothelial damage by means of giving rats an injection of adrenalin and making it swim in ice-cold water, then measuring the number of circulating endothelial cells (CEC) in whole blood and rheology. Moreover observing the change of the above indexes after the rats have taken Leech, Radix salviae miltrorrhizae (RSM) and its composite recipe for 5 days or 10 days. RESULT: It could increase the number of CEC accompanied by whole blood viscosity, fibrinogen and hematocrit in rats with blood stasis. But for groups taking Chinese medicine, the number of CEC was decreased distinctively and blood rheology was improved. CONCLUSION: The rat with blood stasis syndrome suffered from obvious injury of VEC. The Leech, RSM and its composite recipe could protect VEC.
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Medicamentos Herbarios Chinos/farmacología , Endotelio Vascular/efectos de los fármacos , Sanguijuelas , Medicina Tradicional China , Salvia miltiorrhiza , Animales , Recuento de Células , Combinación de Medicamentos , Medicamentos Herbarios Chinos/aislamiento & purificación , Endotelio Vascular/citología , Femenino , Hemorreología/efectos de los fármacos , Sanguijuelas/química , Masculino , Materia Medica/aislamiento & purificación , Materia Medica/farmacología , Plantas Medicinales/química , Ratas , Ratas Wistar , Salvia miltiorrhiza/químicaRESUMEN
UNLABELLED: Inhibition of cyclooxygenase (COX)-2 elicits therapeutic effects in solid tumors that are coupled with the inhibition of cell proliferation and induction of apoptosis in tumor cells. AIM: This study was designed to investigate the role of COX-2 inhibitor nimesulide in cell growth and apoptosis of the cultured human hepatocellular carcinoma HepG2 cells. METHODS: We performed the MTT assay, flow cytometric analysis and cell morphology study to evaluate growth inhibition and cell apoptosis upon the action of nimesulide alone or along with doxorubicin, a common agent for the treatment of human hepatocellular carcinoma. RESULTS: Our results showed that the treatment of HepG2 cells with more than 50 microM of nimesulide suppressed COX-2 enzyme activity because of reduced PGE(2) production, and then induced growth inhibition and cell apoptosis despite no alterations of COX-2 protein expression. Importantly, the combination of 50 microM or 100 microM of nimesulide and low concentrations (5 microM to 20 microM) of doxorubicin resulted in enhanced cell growth inhibition, apoptosis induction and reduced VEGF production. CONCLUSION: These data suggest synergistic and/or additive effects of COX-2 inhibitors and chemotherapeutic agents, and may provide the rational for clinical studies of COX-2 inhibitors on the treatment or chemoprevention of human hepatocellular carcinoma.
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Apoptosis/efectos de los fármacos , Carcinoma Hepatocelular/tratamiento farmacológico , Proliferación Celular/efectos de los fármacos , Inhibidores de la Ciclooxigenasa 2/farmacología , Doxorrubicina/farmacología , Neoplasias Hepáticas/tratamiento farmacológico , Sulfonamidas/farmacología , Carcinoma Hepatocelular/metabolismo , Carcinoma Hepatocelular/patología , Ciclooxigenasa 2/metabolismo , Combinación de Medicamentos , Humanos , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Proteínas de la Membrana/metabolismo , Células Tumorales Cultivadas/efectos de los fármacos , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
OBJECTIVE AND DESIGN: To investigate the therapeutic effects and mechanisms of total glucosides of paeony (TGP), an effective compound of Chinese traditional herbal medicine (CTM), on collagen -induced arthritis (CIA) in rats. MATERIALS: CIA was induced in male Sprague-Dawley rats immunized with chicken type II collagen in Freund's complete adjuvant. TREATMENT: TGP (25, 50, 100 mg/kg/d) was orally administered to rats from day 14 to 28 after immunization. METHODS: Arthritis was evaluated by hind paw swelling, polyarthritis index, and histological examination. Activities of interleukin-1 (IL-1) and tumor necrosis factor alpha (TNFalpha) were determined and the ultrastructure of synoviocytes was observed. The proliferation and the production of vascular epidermal growth factor (VEGF), basic fibroblast growth factor (bFGF), matrix metalloproteinase 1 (MMP-1) and MMP-3 in fibroblast-like synoviocytes (FLS) were detected. RESULTS: The administration of TGP (25, 50, 100 mg/kg, ig x 14 days) suppressed secondary inflammatory reactions and histological changes in CIA model. The ultrastructure of synoviocytes from CIA rats was changed, and the level of IL-1 and TNF alpha produced by macrophage-like synoviocytes (MLS) from CIA rats was elevated. TGP (50, 100 mg/kg, ig x 14 days) inhibited above changes significantly. The MLS supernatants of CIA rats induced more cell proliferation and more production of VEGF, bFGF, MMP-1 and MMP-3 in FLS of CIA than those supernatants from CIA rats treated with TGP (50, 100 mg/kg, ig x 14 days). CONCLUSION: These results indicate that TGP exerts a suppressive effect on joint destruction in rat CIA. The therapeutic effect of TGP could be associated with its ability to ameliorate the secretion and metabolism of synoviocytes and to inhibit the abnormal proliferation and VEGF, bFGF, MMP-1 and MMP-3 production by FLS.
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Artritis Experimental/tratamiento farmacológico , Artritis Experimental/patología , Colágeno/metabolismo , Glucósidos/química , Articulaciones/patología , Paeonia/metabolismo , Animales , Western Blotting , Proliferación Celular , Pollos , Medicamentos Herbarios Chinos , Factores de Crecimiento de Fibroblastos/metabolismo , Glucósidos/metabolismo , Historia del Siglo XVIII , Inflamación , Interleucina-1/metabolismo , Articulaciones/efectos de los fármacos , Masculino , Metaloproteinasa 1 de la Matriz/metabolismo , Metaloproteinasa 3 de la Matriz/metabolismo , Metaloproteinasas de la Matriz/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratas , Ratas Sprague-Dawley , Membrana Sinovial/citología , Membrana Sinovial/ultraestructura , Factores de Tiempo , Factor A de Crecimiento Endotelial Vascular/metabolismoRESUMEN
Although the genome organization and overall structure of hepatitis A virus are similar to those of other picornaviruses, nothing is known about the protein-processing pathways used by this virus to generate its capsid and nonstructural proteins from the polyprotein precursor. RNA transcripts of cloned hepatitis A virus cDNAs representing parts of the P2 and P3 regions of the genome were translated in rabbit reticulocyte lysates in vitro, and the translation products were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis before and after immunoprecipitation with specific antisera. Pulse-chase experiments demonstrated rapid cleavage at the P2-P3 junction, followed by further but incomplete processing at the 3C-3D junction. Mutation of the 3C coding sequence eliminated all cleavages. Efforts to demonstrate intermolecular cutting of the P2-P3 cleavage site by active 3C or 3CD sequences were unsuccessful; thus, it is likely that this cleavage occurs by intramolecular reaction, in cis.
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Cisteína Endopeptidasas/metabolismo , Hepatovirus/enzimología , Biosíntesis de Proteínas , Procesamiento Proteico-Postraduccional , Proteínas Virales/metabolismo , Proteasas Virales 3C , Secuencia de Aminoácidos , Animales , Cisteína Endopeptidasas/genética , Electroforesis en Gel de Poliacrilamida , Datos de Secuencia Molecular , Mutación , Pruebas de Precipitina , ARN Viral/metabolismo , Conejos , Proteínas Virales/genéticaRESUMEN
Subgenomic hepatitis A virus (HAV) RNA sequences were translated in vitro to produce proteins representing the structural (P1) and nonstructural (P2 and P3) domains of the viral polyprotein. These proteins were used as antigens to detect the presence of antibodies in sera from acute and convalescent humans and an experimentally infected chimpanzee. All infected individuals tested had antibodies that recognized uncleaved P1 proteins as well as nonstructural proteins. Antibodies in sera from infected individuals recognized conformation-dependent epitopes that were sensitive to SDS and heat treatment. Time-course studies of the experimentally infected chimpanzee showed that antibodies to the HAV proteins were detectable between 24 and 31 days after infection and persisted for greater than 6 months. Human sera remained positive for antibodies to both structural and nonstructural antigens for at least 2 1/2 years. The data suggest that HAV nonstructural proteins could be used as serologic markers for HAV diagnosis and for evaluating field trials of inactivated vaccines.
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Hepatitis A/inmunología , Anticuerpos Antihepatitis/biosíntesis , Hepatovirus/inmunología , Proteínas Virales/inmunología , Proteínas Estructurales Virales/inmunología , Animales , Antígenos Virales/inmunología , Electroforesis en Gel de Poliacrilamida , Anticuerpos de Hepatitis A , Hepatovirus/genética , Humanos , Cinética , Pan troglodytes , Pruebas de Precipitina , Biosíntesis de Proteínas , ARN Viral/química , Conejos , Proteínas Recombinantes/inmunologíaRESUMEN
Hepatitis A virus (HAV), a RNA virus of positive polarity, contains a long 5' noncoding region (5'NCR) that lacks the characteristic m7GpppN cap group of most eukaryotic messages. By creating bicistronic constructs that contain the bacterial chloramphenicol acetyltransferase gene followed by the HAV 5'NCR and the luciferase gene we have demonstrated by assaying in vitro and in vivo that ribosome entry for translation initiation occurs via binding to sequences within the HAV 5'NCR. Using mutations created within this region we have identified that the HAV internal ribosome entry site (IRES) is located downstream of nucleotide 45 and including sequences up to nucleotide 734 of the HAV 5'NCR. Translation of a number of mutant constructs both in vitro in a rabbit reticulocyte lysate and in vivo by transfection of the cDNAs into BS-C-1 cells in the presence of the recombinant vaccinia virus, vTF7-3, gave similar results. However, a 4-nucleotide insertion at base 628 showed an increased activity over wild-type when transfected into BS-C-1 cells that was not seen in vitro. This increase in activity correlated with an increase in luciferase gene product as assayed by immunoprecipitations of [35S]methionine radiolabeled cells. Comparison of mono- and bicistronic RNAs that were synthesized with or without a m7GpppG cap group showed a competition for ribosome binding when translated in a rabbit reticulocyte lysate system. The presence of the cap group on the RNA 5'terminus of the RNA led to a greater ability of this RNA to translate than the RNA containing the HAV IRES.
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Genes Virales , Hepatovirus/fisiología , ARN Viral/genética , Ribosomas/metabolismo , Proteínas Estructurales Virales/genética , Animales , Secuencia de Bases , Línea Celular , Cloranfenicol O-Acetiltransferasa/genética , Cloranfenicol O-Acetiltransferasa/metabolismo , ADN Viral/genética , Hepatovirus/genética , Luciferasas/genética , Luciferasas/metabolismo , Modelos Estructurales , Datos de Secuencia Molecular , Conformación de Ácido Nucleico , Oligodesoxirribonucleótidos , Plásmidos , Reacción en Cadena de la Polimerasa/métodos , Biosíntesis de Proteínas , ARN Viral/química , Proteínas Recombinantes/metabolismo , Mapeo Restrictivo , Eliminación de Secuencia , Transcripción GenéticaRESUMEN
Portions of the P1 and P2 hepatitis A virus (HAV) polyprotein were generated by in vitro translation of cDNA transcripts and analyzed for a primary cleavage reaction that would release the capsid protein precursor. No autocatalytic activity was observed on either side of the 2A coding sequence. Incubation of these proteins with an extract containing active HAV 3C protease, however, resulted in cleavage at a position approximately 40 amino acids downstream of the previously proposed P1-2A junction. This cleavage site likely accounts for the VP1-containing proteins of approximately 38-40 kDa observed in HAV-infected cells.
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Cápside/metabolismo , Hepatovirus/metabolismo , Precursores de Proteínas/metabolismo , Proteínas Virales , Proteasas Virales 3C , Cápside/genética , Cisteína Endopeptidasas/metabolismo , Hepatovirus/genética , Precursores de Proteínas/genéticaRESUMEN
Sera from recent and past cases of poliomyelitis as well as from healthy subjects vaccinated with live attenuated poliovirus, all contain antibodies to poliovirus nonstructural proteins. Reactivity of these antisera with nonstructural protein antigens present in virus-infected HeLa cells or translated from cDNA transcripts in rabbit reticulocyte lysates was sometimes sensitive to denaturation of the antigens. The finding of antibodies to nonstructural proteins of poliovirus and other viruses should have applications in the development of diagnostic assays for virus infection and may have implications for future vaccine design.